This invention pertains to a purge system in a refrigeration system, and more particularly to a purge probe for withdrawing noncondensible gases and other contaminants from a condenser.
Within refrigeration systems, various noncondensible gases and other contaminants normally become mixed with refrigerant and tend to collect at some point in the refrigeration system. In those refrigeration systems wherein the evaporator operates under a partial vacuum, noncondensible gases and other contaminants tend to concentrate generally at the central portion of the condenser. The presence of noncondensible gases and other contaminants in the refrigeration system reduces the efficiency thereof. For example, when noncondensible gases and refrigerant vapor mix in the condenser, this gaseous mixture blankets the condenser tubes and thus reduces the transfer of heat thereto. Further, the capacity of the refrigeration system is reduced since the noncondensible gases displace refrigerant vapor flowing through the refrigeration system.
Various schemes have been previously utilized to remove noncondensible gases and other contaminants concentrating within the condenser and about the condenser tubes. For example, in some condensers, divider plates are inserted into the condenser to separate the condenser tubes into sections of differently directed flow paths for the cooling fluid, such as water. Because of the insertion of the divider plates, some of the condenser tubes are spaced further apart than normal and it is within this spaced apart area that purge probes have been positioned to withdraw noncondensible gases and other contaminants. One of the problems with this arrangement is that the fluid flow is generally greater in the separated areas and thus do not provide a true or optimum sampling or withdrawal of contaminants.
Another earlier arrangement for positioning a purge probe is to insert the probe just inside the inner peripheral surface of the condenser shell. This is an undesirable location since the noncondensible gases and other contaminants tend to concentrate generally at the center of the condenser.